Three flowers in a corner of a darkened room, shining in different colors.

LED Flower Bouquet Is A Radiant Hacker Desk Decoration

March 15, 2022 by Arya Voronova 4 Comments

[Jeremy Cook] writes to us about a project of his – a bouquet of LED cube flowers. The flowers are PCB cubes made out of small castellated PCBs, each of those having an individually addressable LED in its center. Castellations hold the cubes together mechanically, and thanks to a cleverly chosen pinout, only two different kinds of PCB need to be ordered for building such a flower!

As a vase for these flowers, he decided to use a glass bottle – which would need a cutout to fit a ESP8266-powered NodeMCU board, a controller of choice for the project. After a few different approaches for cutting glass all resulted in the bottles cracking, he gave up on the “clean cut” idea and reused one of the broken bottles, gluing it back together well enough for the aesthetic to work.

[Jeremy] tells us that he’s had help from a hack we covered back in 2017 – using a diode for level shifting, as the ESP8266’s 3.3 V level signals aren’t a good match for WS2812 inputs. From there, the WLED firmware for the ESP8266 ties everything together beautifully. It’s clear that [Jeremy] had a field day designing this, toying with all the ideas and approaches!

Colorful LEDs are a must-have for decorating hacker homes. From a bouquet of flowers, you might find yourself sketching a castellated PCB tile design, and next thing you know, you’ve created a beautiful system of LED triangle tiles. Some PCB fabs scoff at castellations, and if that’s the case, you might as well finish the job yourself.

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Cheap Ghostbusters Toy Turned Convincing Prop

March 14, 2022 by Tom Nardi 2 Comments

As you might expect, the release of last year’s Ghostbusters: Afterlife has not only lead to renewed interest in the old 1980s toys and tie-in merchandise, but has spawned a whole new generation of blinking plastic gadgets to delight children of all ages. Of course, for folks like us, that means more hardware to hack on.

In a recent post to the official Ghostbusters YouTube channel, professional prop maker [Ben Eadie] shows off some of the tricks of the trade when he takes a $15 USD “PKE Meter” toy from Hasbro and turns it into a screen-quality prop. Even if you’re not looking to get an early start on your Halloween costume, the techniques demonstrated in this video could be easily adapted to other projects. For those whose next ideal home improvement is a fireman’s pole and an ectoplasmic laser-confinement grid, you might want to grab a couple of these toys while they’re still cheap for eventual conversion.

Uncovering the silver makes the piece look worn down.

The biggest takeaway from the video is probably the finishing techniques, as they could be used on any sort of realistic prop build. [Ben] starts by using a cabinet scraper to smooth out the lines on the plastic toy, and any holes are filled with the familiar baking soda and cyanoacrylate glue trick. Once the surfaces have been prepped, all the principle parts are sprayed with an adhesion promoter, followed by a coat of silver, and then the final black color.

This allows him to create a convincing “chipped paint” effect by strategically sanding or scraping through the top coat. Dabbing some toothpaste where you want the device to look worn down before spraying the final coat makes the process even faster, as it will prevent the top coat from sticking to the silver in the first place.

Unfortunately [Ben] doesn’t spend a whole lot of time explaining the electronics side of things, but it doesn’t look like there’s anything too complex going on. All the original gear is stripped, and it gets replaced with a microcontroller which we believe is an Adafruit ItsyBitsy nRF52840 Express. This is connected to two strings of tiny APA102 addressable LEDs which are run down the “wings” (we especially like the 3D printed lenses used to replace the original solid pips), and one that’s used to provide the iconic sine-wave display.

While the last PKE meter build we saw did detect radiation, we have to admit that in terms of looks, this one takes the top spot. Especially when you consider how cheap the thing was. All you need now is a Proton Pack, and you’ll be ready for Halloween.

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Big LED Matrix Becomes Tiny LED Matrix Thanks To Fiber Optics

March 1, 2022 by Dan Maloney 11 Comments

Everyone loves LED matrices, and even if you can’t find what you like commercially, it’s pretty easy to make just what you want. Need it big? No problem; just order a big PCB and some WS2812s. Need something tiny? There are ridiculously small LEDs that will test your SMD skills, as well as your vision.

But what if you want a small matrix that’s actually a big matrix in disguise? For that, you’ll want to follow [elliotmade]’s lead and incorporate fiber optics into your LED matrix. The build starts with a 16×16 matrix of WS2812B addressable LEDs, with fairly tight spacing but still 160 mm on a side. The flexible matrix was sandwiched between a metal backing plate and a plastic bezel with holes directly over each LED. Each hole accepts one end of a generous length of flexible 1.5-mm acrylic light pipe material; the other end plugs into a block of aluminum with a 35 by 7 matrix of similar holes. The small block is supported above the baseplate by standoffs, but it looks like the graceful bundle of fibers is holding up the smaller display.

A Raspberry Pi Pico running a CircutPython program does the job of controlling the LEDs, and as you can see in the video below, the effect is quite lovely. Just enough light leaks out from the fibers to make a fascinating show in the background while the small display does its thing. We’ve seen a few practical uses for such a thing, but we’re OK with this just being pretty. It does give one ideas about adding fiber optics to circuit sculptures, though.

Continue reading “Big LED Matrix Becomes Tiny LED Matrix Thanks To Fiber Optics” →

Image showing differences between WS2815 and WS2813 LED strips - the WS2815 strip lighting is more uniform throughout the strip's length.

Teaching You Everything You Might Have Missed About Addressable LEDs

February 27, 2022 by Arya Voronova 11 Comments

Often, financial motivation results in people writing great educational material for hackers. Such is absolutely the case with this extensive documentation blog post on addressable LEDs by [DeRun]. This article could very be named “Addressable LEDs 101”, and it’s a must-scroll-through for anyone, whether you’re a seasoned hacker, or an artist with hardly any technical background and a desire to put LEDs in your creations.

This blog post is easy to read, painting a complete picture of what you can expect from different addressable LED types, and with apt illustrations to boot. Ever wonder which one of the addressable strips you should get from your retailer of choice, and what are the limitations of any specific type? Or, perhaps, you’d like to know – why is it that a strip with a certain LED controller is suspiciously cheap or expensive? You’re more than welcome to, at least, scroll through and fill into any of your addressable LED knowledge gaps, whether it’s voltage drops, color accuracy differences, data transfer protocol basics or dead LED failsafes.

Addressable LEDs have a special place in our hearts, it’s as if the sun started shining brighter after we’ve discovered them… or, perhaps, it’s all the LEDs we are now able to use. WS2812 is a staple of the addressable LED world, which is why we see them even be targets of both clone manufacturers and patent trolls. However, just like the blog post we highlight today mentions, there’s plenty of other options. Either way do keep coming cover a new addressable LED-related hack, like rewriting their drivers to optimize them, or adding 3.3V compatibility with just a diode.

We thank [Helge] for sharing this with us!

Levitating With Light

February 23, 2022 by Al Williams 31 Comments

The University of Pennsylvania has a team that did a little light research. Well, not light in the usual sense of that phrase. They used very strong light to levitate Mylar disks in a vacuum chamber.

Of course, it is no secret that light can exert pressure. That’s how solar sails work and some scientists have used it to work with aerosols and the like. But this appears to be the first time light lifted a large item against gravity. The team claims that their tests showed that a sunlight-powered flying vehicle might carry up to ten milligrams of payload. That doesn’t sound like much, but it’s impressive and the paper mentions that since the lift is not from aerodynamic forces, there might be applications in flying at very high altitudes.

The Mylar disks were 500 nanometers thick and had a 300 nanometer layer of carbon nanotubes beneath. The nanotubes absorb light, make the disks more rigid, and improve the Mylar’s surface-gas characteristics. The light source had a strong center beam and an even stronger ring around the center beam that causes the disk to remain over the center beam. The LED system used eight arrays, each consuming 100 watts of input power.

Preparing the disk might be difficult, but the LED power isn’t that hard. Even if you do like the researchers did and use water cooling.

A Ball Lens For Optical Fiber Coupling On The Cheap

February 21, 2022 by Jenny List 16 Comments

It’s fair to say that for most of us, using a fiber optic cable for digital audio or maybe networking will involve the use of an off-the-shelf termination. We snap the cable into the receptacle, and off we go. We know that inside there will be an LED and some lenses, but that’s it. [TedYapo] though has gone a little further into the realm of fibers, by building his own termination. Faced with the relatively high cost of the ball lenses used to focus light from an LED into the end of the fiber he started looking outside the box. He discovered that spherical glass anti-bumping balls used when boiling fluids in laboratories make an acceptable and much cheaper alternative.

A ball lens has an extremely short focal length, meaning that this same property which allowed Antonie van Leeuwenhoek to use them in his microscopes is ideal for LED focusing in a small space at the end of a fiber. Chromatic aberrations are of no consequence for light of a single wavelength. It seems that the glass balls are uniformly spherical enough to do the job. Fitted with the LED and fiber termination in a 3D-printed block, the relative position of the ball can be controlled for optimum light transfer. It’s a relatively simple hack mentioned in passing in a Twitter thread, but we like it because of its cheapness and also for an insight into the world of optical fiber termination.

Curious to know more about optical fibers? We covered just the video for you back in 2011.

Weird Phosphor Conversion LEDs Found In Cheap LED String

February 16, 2022 by Lewin Day 40 Comments

[Tim] recently found himself tinkering with a cheap string of LEDs. Far from an advanced, IC-controlled addressable set, these were merely a string with LEDs of four colors that could be switched on and off. However, digging in to the LEDs themselves turned up a curious find.

The LEDs were set up in a parallel/anti-parallel fashion. The two power lines ran the length of the string, with all the LEDs installed across them. If polarity was applied in one direction, the red and yellow LEDs would light up, in the other, the blue and green LEDs would light together.

This raised a question for [Tim], as typically, different LEDs light up at different forward voltages and this can cause issues when running different color LEDs in parallel together. What he instead found was that all the LEDs were actually blue LEDs in their fundamental construction. However, the red, yellow, and green LEDs had all been given a phosphor coating. In these devices, when the blue LED underneath lit up, the phosphor converted the light into the desired color. [Tim] was able to confirm this behaviour by illuminating the phosphor manually using an external UV-A LED.

It’s an interesting choice, but it’s certainly one way of making a multicolored string of LEDs. If you wanna get fancier though, consider studying this tutorial on working with addressable LED strings!

[Thanks to J Peterson for the tip!]